The present invention relates to a process for producing 4-(4-methyl-4-hydroxyamyl)-.DELTA..sup.3 -cyclohexenecarboxaldehyde in good yields and under relatively mild conditions; and the uses in perfumery of the products produced by such process.
The Diels-Alder reaction is well known in the field of organic chemistry, and the classic example thereof is the reaction of a conjugated diene with a conjugated alkylene carbonyl compound to provide a cyclic compound with unsaturation in the cyclic moiety. Since the original reaction was set forth, there have been many variations of the reaction. While certain compounds such as maleic anhydride and conjugated dienes react at room temperature to form cyclic derivatives, many other similar reactions require the use of more aggressive reaction conditions, and in many instances even these conditions do not provide very good yields of cyclic product.
4-(4-METHYL-4-HYDROXYAMYL)-.DELTA..sup.3 -CYCLOHEXENECARBOXALDEHYDE IS INDICATED TO BE PRODUCED IN U.S. Pat. No. 2,947,780, issued on Aug. 2, 1960, by means of reaction acrolein with myrcenol in a sealed reactor and heating the reaction mass to 150.degree. C for a period of 4-1/2 hours accompanied by agitation. The reaction mass is then allowed to cool and the contents removed and subjected to fractional distillation. No mention of the use of a Lewis acid catalyst is set forth in U.S. Pat. No. 2,947,780.
U.S. Pat. No. 3,433,839 discloses a more complex process for preparing compounds having a structure similar to those prepared in the instant. U.S. Pat. No. 3,433,839 discloses a process for producing a mixture of alicyclic hydroxyaldehydes which comprises:
I. photo-oxidizing myrcene to produce a mixture of its hydroperoxides, PA1 Ii. reducing the resulting mixture to produce a mixture of 2-methyl-6-methylene-3,7-octadiene-2-ol and 2-methyl-6-methylene-1,7-octadiene-3-ol; and PA1 Iii. reacting the thus obtained mixture with a dienophile selected from the group consisting of acrolein and crotonaldehyde at 100.degree. to 150.degree. C for 3 to 6 hours to produce at least one mixture of alicyclic hydroxyaldehydes selected from the group consisting of where said dienophile is acrolein, 4-(4'-methyl-4'-hydroxy-2'-pentenyl)-3-cyclohexene-1-carboxaldehyde and 4-(4'-methyl-3'-hydroxy-4'-pentenyl)-3-cyclohexene-1-carboxaldehyde, and where said dienophile is crontonaldehyde, 4-(4'-methyl-4'-hydroxy-2'-pentenyl)-6-methyl-3-cyclohexene-1-carboxaldehy de and 4-(4'-methyl-3' -hydroxy-4'-pentenyl)-6-methyl-3-cyclohexene-1-carboxaldehyde. PA1 1. H. G. Oddy, J. Amer. Chem. Soc., 45,2156 (1923). aluminum chloride catalyzed Diels-Alder reaction of anthracene and maleic anhydride. PA1 2. A. N. Johnson, U.S. Pat. No. 2,724,730 (1955); CA, 51,7409b (1957). AlCl.sub.3 catalyzed reaction of hexachlorocyclopentadiene with cyclopentene and hexachlorocyclopentene. PA1 3. P. Yates and P. Eaton, J. Amer. Chem. Soc. 82,4436 (1960). AlCl.sub.3 catalyzed reaction of anthracene and maleic anhydride. PA1 4. G. I. Fray and R. Robinson, J. Amer. Chem. Soc., 83,249 (1961); U.S. Pat. No. 3,067,244 (1962). Lewis acid catalyzed Diels-Alder reaction of butadiene, cyclopentadiene, or anthracene with various dienophiles (e.g., acrolein, methacrolein, acrylic aicd, methyl vinyl ketone). Only dienophiles having a terminal vinyl group are claimed. PA1 5. H. M. Walborsky, L. Barash and T. C. Davis, J. Org. Chem., 26,4778 (1961); Tetrahedron, 19,233 (1963). AlCl.sub.3 catalyzed reaction of butadiene and (-)-dimenthyl fumarate. PA1 6. I. A. Favorskaya and E. M. Auvinen, Zh. Obshch. Khim., 33,2795 (1963); CA, 59,15191 d. BF.sub.3 catalyzed reaction of isoprene or 2,3-dimethylbutadiene-1,3 with methyl vinyl ketone. 2-hexen-4-one, 1-propionylcyclopentene, and 1-propionylcyclohexene. PA1 7. E. F. Lutz and G. M. Bailey, J. Amer. Chem. Soc., 86,3899 (1964). Comparison of isomer ratio of thermal and SnCl.sub.4 catalyzed reaction of isoprene with acrolein or methyl vinyl ketone. PA1 8. a. T. Inukai and M. Kasai, J. Org. Chem., 30,3567 (1965). b. T. Inukai and T. Kojima, J. Org. Chem., 31,1121 (1966). Lewis acid catalyzed reaction of isoprene with various acrylic acid derivatives. PA1 9. British Pat. No. 1,076,304 (1965); CA, 68,49177 f (1968). AlCl.sub.3 catalyzed reaction of methyl acrylate, methyl methacrylate, or acrylonitrile with isoprene, piperylene, chloroprene, cyclopentadine, or 1,3-butandiene. (cf. U.S. Pat. No. 3,390,169). PA1 10. G. P. Kugatova-Shemyakina, L. I. Rozhkova, V. N. Gramenitskaya and V. M. Andreev. J. Org. Chem. USSR, 62,459 (1970). Catalysis of the reaction of acrolein or crotonaldehyde with isoprene or piperylene. PA1 11. S. R. Wallis. J. Amer. Chem. Soc., 92,3218 (1970). AlCl.sub.3 catalyzed Diels-Alder reaction of butadiene with 2-phenyl-2-cyclohexenone. PA1 12. French Pat. No. 2,149,051, D. De Ryke and H. Boelens. ZnCl.sub.2 catalysis of Diels-Alder reaction of 2-hexenal with 2-methyl-1,3-pentadiene and with cyclopentadiene.
The prior art is replete with disclosures of Diels-Alder reactions wherein Lewis acids are used as catalysts, as follows:
In addition, Lewis acid catalyzed Diels-Alder reactions wherein the dienophile is alpha,beta-disubstituted with alkyl groups are disclosed in U.S. Pat. No. 3,852,358, issued on Dec. 3, 1974.
British Pat. No. 1,383,942, published on Feb. 12, 1975 disclosed processes for producing 6-propyl-3-cyclohexene carboxalhydes of the general formula: ##STR3## and processes for producing same wherein an alkadiene of the general formula: ##STR4## undergoes a Diels-Alder reaction with 2-hexene-1-al. In Example I, of British Pat. No. 1,383,942, 2-methyl-1,3-pentadiene is shown to be reacted with 2-hexene-1-al in the presence of a zinc chloride catalyst at reflux temperature, 75.degree. C. However, the reaction mass is maintained at 120.degree. C for 1 hour and it is indicated that this reaction must maintained at the higher temperature for that period of time.
German Offenlegungschrift No. 2,403,631, published on Aug. 8, 1974, discloses a process for producing such compounds as 3-methyl-5-(3-methyl-3-hydroxy-butyl)-3-cyclohexenecarboxaldehyde the last step of which is a thermal, non-catalytic Diels-Alder reaction: ##STR5##
U.S. Pat. No. 2,373,568 shows the Diels-Alder reaction of methacrolein and cyclopentadiene under pressure at about 140.degree. C to provide a material with a camphoraceous aroma and the further reaction of the Diels-Alder product with acetone and sodium methylate to provide a product with a floral type odor. Vaughan et al. in J.A.C.S. 74,5355show the reaction of mesityl oxide and cyclopentadiene produced in situ by thermal depolymerization of the dimer to provide an unsaturated ketone by carrying out the reaction at 160.degree. C for 12 hours to provide a 21 percent yield, based upon cyclopentadiene, although the yield based upon mesityl oxide consumed was said to be 60 percent.
Chemical Abstracts 47, 12271e shows a diene condensation at 160.degree. C in the presence of pyrogallol. A condensation of isoprene and other materials with mesityl oxide at 200.degree. C is shown in Chemical Abstracts 72, 8985p. The use of haloacetic acids as catalysts in diene reactions is shown in French Patent No. 838,454. Wasserman concluded that diene synthesis rates were not appreciably affected by a number of catalysts including ferric chloride in ethanol in J. Chem. Soc. 3346 (1949).
Chemical Reviews 31, 441 reported a reaction between anthracene, maleic anhydride and aluminum chloride. U.S. Pat. No. 2,724,730 shows the condensation of hexachlorocylopentadiene with a dienophilic compound in the presence of alumiumn chloride at 100.degree. C. Aluminum Chloride is said to catalyze a Diels-Alder reaction in J. Org. Chem. 26, 4778. The International Edition of Angew. Chem. 6, 24 states that Lewis-acids have an effect on the yields of stereoisomers in diene additions and mentions the possibility of an investigation of reaction at low temperature in the presence of Lewis-acids under mild conditions to obtain uniform Diels-Alder Products. A low temerature Diels-Alder reaction is shown in Chemical Abstracts 59, 15191d, and regulation of structural isomerism and acceleration of Diels-Alder reaction is shown in J.A.C.S. 86, 3899. Diels-Alder reactions catalyzed by aluminum chloride are also shown in J. Organic. Chem. 32, 1121. See also Tetrahedron 19, 2333 (1963).
The Diels-Alder reaction of certain aldehydes with dienes in the presence of stannic chloride and boron trifluoride is shown in a translation of an article from Zh. Org. Chimii 6, 2446. Dienophilic compounds for Diels-Alder reactions are shown in Chemical Review 31, 327 and in Onishchenko, Diene Synthesis at page 904ff. British Patent No. 835,840 (also J.A.C.S. 82,4436) shows acceleration of the Diels-Alder reaction with stannic chloride. Acceleration with aluminum chloride is shown in J.A.C.S. 82,4436. U.S. Pat. Nos. 3,047,433 and 3,067,244 show the use or production of Diels-Alder adducts.
British Patent Specification No. 1,076,304 shows a Diels-Alder reaction to produce nitriles and esters. Thus, nothing in the prior art is considered to teach explicitly or implicitly a low temperature reaction to produce mixtures containing a high proportion of 4-(4-methyl-4-hydroxyamyl)-.DELTA..sup.3 -cyclohexenecarboxaldehyde.